Am J Perinatol 2017; 34(01): 31-37
DOI: 10.1055/s-0036-1584137
Original Article
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Birth Weight by Gestational Age for 76,710 Twins Born in the United States as a Result of In Vitro Fertilization: 2006 to 2010

Richard P. Dickey
1  Section of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, Louisiana State University School of Medicine, New Orleans, Louisiana
2  The Fertility Institute of New Orleans, New Orleans, Louisiana
,
Gabriella Pridjian
3  Department of Obstetrics and Gynecology, Tulane University School of Medicine, New Orleans, Louisiana
,
Xu Xiong
4  Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana
,
Monica C. Klempel
2  The Fertility Institute of New Orleans, New Orleans, Louisiana
› Author Affiliations
Further Information

Publication History

14 November 2015

11 March 2016

Publication Date:
16 May 2016 (online)

Abstract

Objective The objective of this study was to establish twin-specific birth weight percentiles by gestational age using U.S. twin births resulting from in vitro fertilization (IVF).

Study Design A retrospective analysis of birth weight by completed weeks of gestation for 76,710 twin IVF births reported to the Society for Assisted Reproductive Technologies from 2006 to 2010. Mean and median birth weights and 3rd, 5th, 10th, 25th, 50th, 75th, 90th, and 97th percentiles were calculated by completed week of gestation and infant sex.

Results IVF twin birth weight accelerates until term and then declines. The deceleration in twin birth weight occurs at 39 completed weeks of gestation for larger twins, those at or above the 50th percentile in weight. For smaller twins, the growth deceleration occurs earlier, at 38 weeks of gestation. IVF female and male twin birth weights for gestational age were similar to all IVF twins, showing similar decelerations near term.

Conclusion Using U.S. IVF twin-specific growth charts, with known date of conception, twins demonstrate a deceleration in birth weight near term. Larger twins demonstrate a deceleration in birth weight by 39 completed weeks of gestation; smaller twins show a deceleration at 38 weeks. These data may assist in the clinical management of twins near term.